The new movie “Ender’s Game,” in theaters Friday, presents a frighteningly bleak portrait of future life on Earth: Mankind is in peril after attacks by an evil alien race called the Buggers, who, true to their name, look like mutant insects.

Our world’s only hope for a hero? A kid.

Asa Butterfield plays the titular teen in question, selected to undergo rigorous training, including a complicated computer mind-teaser and ruthless war games.

But, according to Butterfield, none of this compares to the most terrifying preparation he had to endure onset.

“Meeting Harrison Ford is always a bit scary,” he says, with a laugh.

Ford plays a military official in the film, which also stars Ben Kingsley as a Battle School training leader, Hailee Steinfeld as another student and Abigail Breslin as Ender’s protective sister. Based on a 1985 novel by Orson Scott Card, the plot touches on themes of manipulation and fear of a foreign enemy.

“It’s made me a lot more aware of what goes on in society and especially things about leadership and children and warfare,” Butterfield says. “How it’s happening around the world, [even if] we may not like to accept that it’s happening. This film attacks it in a slightly different way, but it still allows you to think about it.”

Truth be told, the 16-year-old explains, “I’m not scared of supernatural things, like aliens, or things that aren’t real. What scares me more is the things which could be real. Murder — but quite creepy murder, like psychological stuff.”

The actor was born Asa Maxwell Thornton Farr Butterfield in London. Unlike many child stars, he wasn’t pushed into the business by his parents. Rather, when Butterfield was 7 years old, he was discovered by a casting director at an after-school program at the Young Actors Theatre.

“He wanted me to join their agency, and so I was like, ‘Sure!’ ” says Butterfield. “I didn’t know what any of that meant at the time.”

It meant a huge career boost for the young actor. With a few small roles under his belt, Butterfield broke out in a big way, starring as Bruno in the 2008 Holocaust drama, “The Boy in the Striped Pajamas.” After parts in “The Wolfman” and “Nanny McPhee Returns,” he landed the role of Hugo in Martin Scorsese’s 2011 film of the same name.

“I’m really like any other 16-year-old back at home,” insists Butterfield, who still attends school. “I’m pretty normal apart from all the . . .”

Blockbusters? As such, he prefers to lead his movie-star life during the summer.

“Filming through the summer is great because it lets me focus just on the film rather than having to manage my schoolwork at the same time. But it’s something that I’ve gotten used to,” he says. “It’s never easy — especially now that I’ve got A-levels, which is a big exam in the UK.”

In his free time, Butterfield says he loves to play video games, go to the park and hang out with his friends. But he also has an interest that made him perfect to play Ender.

“I’m a massive science-fiction fan,” he says. “What I really like is how — compared to fantasy, where it’s not physically possible — in sci-fi, a lot of technology that’s in film is already being developed.”

Butterfield cites “The Matrix” as his favorite film in the genre and “The Knife of Never Letting Go” as his favorite sci-fi book, but it’s Ender’s story that’s sticking with him right now. He even says that the lingering fear on set has spilled over into real life.

“It’s not just a science-fiction film. There are a lot of themes and ideas which are really relevant today. Considering it was written 30 years ago is pretty crazy,” he says.

It’s almost as crazy as the boy-wonder actor having to face a harsh reality this Halloween: growing up.

“In London, trick-or-treating is illegal if you’re over 16,” he sighs. “That’s a bit of a bummer.”